Home | History | Annotate | Download | only in Tensor
      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog (at) gmail.com>
      5 //
      6 // This Source Code Form is subject to the terms of the Mozilla
      7 // Public License v. 2.0. If a copy of the MPL was not distributed
      8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
      9 
     10 #ifndef EIGEN_CXX11_TENSOR_TENSOR_ASSIGN_H
     11 #define EIGEN_CXX11_TENSOR_TENSOR_ASSIGN_H
     12 
     13 namespace Eigen {
     14 
     15 /** \class TensorAssign
     16   * \ingroup CXX11_Tensor_Module
     17   *
     18   * \brief The tensor assignment class.
     19   *
     20   * This class is represents the assignment of the values resulting from the evaluation of
     21   * the rhs expression to the memory locations denoted by the lhs expression.
     22   */
     23 namespace internal {
     24 template<typename LhsXprType, typename RhsXprType>
     25 struct traits<TensorAssignOp<LhsXprType, RhsXprType> >
     26 {
     27   typedef typename LhsXprType::Scalar Scalar;
     28   typedef typename traits<LhsXprType>::StorageKind StorageKind;
     29   typedef typename promote_index_type<typename traits<LhsXprType>::Index,
     30                                       typename traits<RhsXprType>::Index>::type Index;
     31   typedef typename LhsXprType::Nested LhsNested;
     32   typedef typename RhsXprType::Nested RhsNested;
     33   typedef typename remove_reference<LhsNested>::type _LhsNested;
     34   typedef typename remove_reference<RhsNested>::type _RhsNested;
     35   static const std::size_t NumDimensions = internal::traits<LhsXprType>::NumDimensions;
     36   static const int Layout = internal::traits<LhsXprType>::Layout;
     37 
     38   enum {
     39     Flags = 0
     40   };
     41 };
     42 
     43 template<typename LhsXprType, typename RhsXprType>
     44 struct eval<TensorAssignOp<LhsXprType, RhsXprType>, Eigen::Dense>
     45 {
     46   typedef const TensorAssignOp<LhsXprType, RhsXprType>& type;
     47 };
     48 
     49 template<typename LhsXprType, typename RhsXprType>
     50 struct nested<TensorAssignOp<LhsXprType, RhsXprType>, 1, typename eval<TensorAssignOp<LhsXprType, RhsXprType> >::type>
     51 {
     52   typedef TensorAssignOp<LhsXprType, RhsXprType> type;
     53 };
     54 
     55 }  // end namespace internal
     56 
     57 
     58 
     59 template<typename LhsXprType, typename RhsXprType>
     60 class TensorAssignOp : public TensorBase<TensorAssignOp<LhsXprType, RhsXprType> >
     61 {
     62   public:
     63   typedef typename Eigen::internal::traits<TensorAssignOp>::Scalar Scalar;
     64   typedef typename Eigen::NumTraits<Scalar>::Real RealScalar;
     65   typedef typename LhsXprType::CoeffReturnType CoeffReturnType;
     66   typedef typename Eigen::internal::nested<TensorAssignOp>::type Nested;
     67   typedef typename Eigen::internal::traits<TensorAssignOp>::StorageKind StorageKind;
     68   typedef typename Eigen::internal::traits<TensorAssignOp>::Index Index;
     69 
     70   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorAssignOp(LhsXprType& lhs, const RhsXprType& rhs)
     71       : m_lhs_xpr(lhs), m_rhs_xpr(rhs) {}
     72 
     73     /** \returns the nested expressions */
     74     EIGEN_DEVICE_FUNC
     75     typename internal::remove_all<typename LhsXprType::Nested>::type&
     76     lhsExpression() const { return *((typename internal::remove_all<typename LhsXprType::Nested>::type*)&m_lhs_xpr); }
     77 
     78     EIGEN_DEVICE_FUNC
     79     const typename internal::remove_all<typename RhsXprType::Nested>::type&
     80     rhsExpression() const { return m_rhs_xpr; }
     81 
     82   protected:
     83     typename internal::remove_all<typename LhsXprType::Nested>::type& m_lhs_xpr;
     84     const typename internal::remove_all<typename RhsXprType::Nested>::type& m_rhs_xpr;
     85 };
     86 
     87 
     88 template<typename LeftArgType, typename RightArgType, typename Device>
     89 struct TensorEvaluator<const TensorAssignOp<LeftArgType, RightArgType>, Device>
     90 {
     91   typedef TensorAssignOp<LeftArgType, RightArgType> XprType;
     92   typedef typename XprType::Index Index;
     93   typedef typename XprType::Scalar Scalar;
     94   typedef typename XprType::CoeffReturnType CoeffReturnType;
     95   typedef typename PacketType<CoeffReturnType, Device>::type PacketReturnType;
     96   typedef typename TensorEvaluator<RightArgType, Device>::Dimensions Dimensions;
     97   static const int PacketSize = internal::unpacket_traits<PacketReturnType>::size;
     98 
     99   enum {
    100     IsAligned = TensorEvaluator<LeftArgType, Device>::IsAligned & TensorEvaluator<RightArgType, Device>::IsAligned,
    101     PacketAccess = TensorEvaluator<LeftArgType, Device>::PacketAccess & TensorEvaluator<RightArgType, Device>::PacketAccess,
    102     Layout = TensorEvaluator<LeftArgType, Device>::Layout,
    103     RawAccess = TensorEvaluator<LeftArgType, Device>::RawAccess
    104   };
    105 
    106   EIGEN_DEVICE_FUNC TensorEvaluator(const XprType& op, const Device& device) :
    107       m_leftImpl(op.lhsExpression(), device),
    108       m_rightImpl(op.rhsExpression(), device)
    109   {
    110     EIGEN_STATIC_ASSERT((static_cast<int>(TensorEvaluator<LeftArgType, Device>::Layout) == static_cast<int>(TensorEvaluator<RightArgType, Device>::Layout)), YOU_MADE_A_PROGRAMMING_MISTAKE);
    111   }
    112 
    113   EIGEN_DEVICE_FUNC const Dimensions& dimensions() const
    114   {
    115     // The dimensions of the lhs and the rhs tensors should be equal to prevent
    116     // overflows and ensure the result is fully initialized.
    117     // TODO: use left impl instead if right impl dimensions are known at compile time.
    118     return m_rightImpl.dimensions();
    119   }
    120 
    121   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(Scalar*) {
    122     eigen_assert(dimensions_match(m_leftImpl.dimensions(), m_rightImpl.dimensions()));
    123     m_leftImpl.evalSubExprsIfNeeded(NULL);
    124     // If the lhs provides raw access to its storage area (i.e. if m_leftImpl.data() returns a non
    125     // null value), attempt to evaluate the rhs expression in place. Returns true iff in place
    126     // evaluation isn't supported and the caller still needs to manually assign the values generated
    127     // by the rhs to the lhs.
    128     return m_rightImpl.evalSubExprsIfNeeded(m_leftImpl.data());
    129   }
    130   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup() {
    131     m_leftImpl.cleanup();
    132     m_rightImpl.cleanup();
    133   }
    134 
    135   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalScalar(Index i) {
    136     m_leftImpl.coeffRef(i) = m_rightImpl.coeff(i);
    137   }
    138   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalPacket(Index i) {
    139     const int LhsStoreMode = TensorEvaluator<LeftArgType, Device>::IsAligned ? Aligned : Unaligned;
    140     const int RhsLoadMode = TensorEvaluator<RightArgType, Device>::IsAligned ? Aligned : Unaligned;
    141     m_leftImpl.template writePacket<LhsStoreMode>(i, m_rightImpl.template packet<RhsLoadMode>(i));
    142   }
    143   EIGEN_DEVICE_FUNC CoeffReturnType coeff(Index index) const
    144   {
    145     return m_leftImpl.coeff(index);
    146   }
    147   template<int LoadMode>
    148   EIGEN_DEVICE_FUNC PacketReturnType packet(Index index) const
    149   {
    150     return m_leftImpl.template packet<LoadMode>(index);
    151   }
    152 
    153   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorOpCost
    154   costPerCoeff(bool vectorized) const {
    155     // We assume that evalPacket or evalScalar is called to perform the
    156     // assignment and account for the cost of the write here, but reduce left
    157     // cost by one load because we are using m_leftImpl.coeffRef.
    158     TensorOpCost left = m_leftImpl.costPerCoeff(vectorized);
    159     return m_rightImpl.costPerCoeff(vectorized) +
    160            TensorOpCost(
    161                numext::maxi(0.0, left.bytes_loaded() - sizeof(CoeffReturnType)),
    162                left.bytes_stored(), left.compute_cycles()) +
    163            TensorOpCost(0, sizeof(CoeffReturnType), 0, vectorized, PacketSize);
    164   }
    165 
    166   /// required by sycl in order to extract the accessor
    167   const TensorEvaluator<LeftArgType, Device>& left_impl() const { return m_leftImpl; }
    168   /// required by sycl in order to extract the accessor
    169   const TensorEvaluator<RightArgType, Device>& right_impl() const { return m_rightImpl; }
    170 
    171   EIGEN_DEVICE_FUNC CoeffReturnType* data() const { return m_leftImpl.data(); }
    172 
    173  private:
    174   TensorEvaluator<LeftArgType, Device> m_leftImpl;
    175   TensorEvaluator<RightArgType, Device> m_rightImpl;
    176 };
    177 
    178 }
    179 
    180 
    181 #endif // EIGEN_CXX11_TENSOR_TENSOR_ASSIGN_H
    182